The precise and accurate location and assembly of blades for turbines is essential. This prevents premature breakdown of the blades and turbines. This invention relates to a tool for verifying the uniformity of blades for turbines and the assembly relationship on a turbine rotor.
The refurbishment of rotor blades for steam turbine owners has an important economic advantage in that the replacement with new blades is avoided. Often refurbished blades can be equal or better than new blades. The time taken for refurbishing can also be less than the time needed to fabricate new blades. Accordingly there is a need for effective blade refurbishment techniques and tools.
One disadvantage in refurbished blades is that blade repair or brazing can cause distortion of reworked parts. Often this distortion is not discovered until the parts are being installed, assembled, or being machine-finished. This difficulty is compounded when reworking is effected in one location and installation is effected in a different location.
To overcome problems of refurbishing, detailed design drawings, gauges such as a guillotine gauge, shutter gauge or box gauge are used to verify the proper blade contours, twist, lean, thickness, in relationship to the radial lines of the disc. Often these different gauges are difficult to obtain or use accurately. Thus engineering and reworking of parts is often difficult if detailed design drawings are not available. When original equipment manufactured parts and non-original equipment manufactured parts are used in combination, problems of tolerance and interchangeability are compounded.
There is accordingly a need to provide for the determination of the blade relationship in assembled condition with regard to neighboring blades and other stationary parts. With such a determination refurbishment and alignment can be more accurately effected.